Feasibility and Optimal Time Point of [68Ga]Gallium-labeled Prostate-specific Membrane Antigen Ligand Positron Emission Tomography Imaging in Patients Undergoing Cytoreductive Surgery After Systemic Therapy for Primary Oligometastatic Prostate Cancer: Imp

Prostate-specific membrane antigen (PSMA) targeted molecular imaging using positron emission tomography (PET) has significantly improved the diagnosis and treatment of prostate cancer (PCA).

To assess the feasibility and compare the diagnostic accuracy of [68Ga]Ga-PSMA-11 PET images taken at baseline, before the initiation of systemic treatment and preoperative images, using histopathology after cytoreductive surgery as reference.

We identified 20 patients in our prospectively maintained database with primary oligometastatic PCA who underwent cytoreductive radical prostatectomy and superextended pelvic lymph node dissection after systemic therapy, who had baseline and preoperative [68Ga]Ga-PSMA-11 PET imaging available.

We performed a region-based analysis to determine the diagnostic accuracy of imaging, using pathology as a reference. Regions were predefined as prostate, internal iliac left/right, obturator left/right, external iliac left/right, common iliac left/right, and presacral.

Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and diagnostic effectiveness were, respectively, 95.65%, 78.22%, 98.39%, 57.89%, and 83.00% for baseline [68Ga]Ga-PSMA-11 PET, compared to 56.52%, 98.05%, 88.30%, 89.66%, and 88.50% for preoperative [68Ga]Ga-PSMA-11 PET. On a receiver operating characteristic analysis, the diagnostic accuracy of baseline [68Ga]Ga-PSMA-11 PET with an area under the curve (AUC) of 0.87 (95% confidence interval [CI] 0.83-0.92) was significantly better than that of preoperative [68Ga]Ga-PSMA-11 PET after systemic therapy with an AUC of 0.77 (95% CI 0.70-0.85, p = 0.01).

Baseline imaging, [68Ga]Ga-PSMA-11 PET has significantly better diagnostic accuracy, sensitivity, and NPV than images obtained preoperatively, in systemically pretreated patients. If a patient is suitable for local treatment and complete resection of the residual tumor is intended, [68Ga]Ga-PSMA-11 PET images taken prior to systemic therapy are significantly more accurate in selecting the relevant lymph nodes for resection.

We found that prostate-specific membrane antigen positron emission tomography (PSMA-PET) imaging used early, before hormonal therapy or chemotherapy, provides more accurate information about the spread of the disease, than if used immediately before surgery but after hormonal therapy or chemotherapy. Early use of PSMA-PET has the potential to improve therapy also at later stages of the disease.

European urology open science. 2022 May 05*** epublish ***

Nicolai Huebner, Sazan Rasul, Pascal Baltzer, Paola Clauser, Karl Hermann Grubm├╝ller, Markus Mitterhauser, Marcus Hacker, Axel Heidenreich, Pawel Rajwa, Harun Fajkovic, Shahrokh F Shariat, Bernhard Grubm├╝ller

Department of Urology, Medical University of Vienna, Vienna, Austria., Department of Biomedical Imaging and Image Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria., Department of Biomedical Imaging and Image Guided Therapy, Division of General and Pediatric Radiology, Medical University of Vienna, Vienna, Austria., Department of Urology and Andrology, University Hospital Krems, Karl Landsteiner University of Health Sciences, Krems, Austria., Department of urology, Uro-oncology, Robot-Assisted and Specialized Surgery, University of Cologne, Cologne, Germany.